Flow Cytometry Textbook Questions

Question 1

Flow cytometry characterizes cells based on all of the following except

a. forward scatter of an interrupted beam of light.
b. side scatter of the interrupted beam of light.
c. fluorescence emitted from the cells.
d. the transmittance of light by cells in solution.

Answer 1

d. the transmittance of light by cells in solution.

Question 2

Forward light scatter is an indicator of a cell’s

a. granularity.
b. density.
c. size.
d. number

Answer 2

c. size.

Question 3

What is the single most important requirement for samples to be analyzed on a flow cytometer?

a. Whole blood is collected into a serum separator tube.
b. Cells must be in a single-cell suspension.
c. Samples must be fixed in formaldehyde before processing.
d. Blood must be kept refrigerated while processing.

Answer 3

b. Cells must be in a single-cell suspension.

Question 4

Which statement represents the best explanation for a flow cytometer’s ability to detect several cell surface markers at the same time?

a. The forward scatter can separate out cells on the basis of complexity.
b. One detector can be used to detect many different wavelengths.
c. For each marker, a specific fluorochrome–antibody combination is used.
d. Intrinsic parameters are separated out on the basis of the amount of side scatter.

Answer 4

c. For each marker, a specific fluorochrome–antibody combination is used.

Question 5

Which of the following cell surface markers would be present on a population of T helper (Th) cells?

a. CD3 and CD4
b. CD3 and CD8
c. CD3 only
d. CD4 only

Answer 5

a. CD3 and CD4

Question 6

If an analyzer consistently indicates a positive test when the analyte in question is not present, this represents a problem with

a. sensitivity.
b. specificity.
c. reportable range.
d. precision.

Answer 6

b. specificity.

Question 7

All of the following are clinical applications for flow cytometry except

a. fetal hemoglobin.
b. immunophenotyping of lymphocyte subpopulations.
c. HIV viral load analysis.
d. enumeration of stem cells in a peripheral blood mononuclear cell product.

Answer 7

c. HIV viral load analysis.

Question 8

The various signals generated by cells intersecting with a flow cytometry laser are captured by

a. bandwidth waves.
b. wave channels.
c. photomultiplier tubes.
d. flow cells.

Answer 8

c. photomultiplier tubes.

Question 9

Analysis of flow cytometer data of cells can be filtered in many ways by using a method of

a. “gating” in a dot plot.
b. banding of a histogram.
c. single-parameter histogram monitoring.
d. automatic sampling.

Answer 9

a. “gating” in a dot plot.

Question 10

A newer flow cytometry technology that has the potential to detect 100 analytes from one sample of blood is called a/an

a. RBC fragmentation assay.
b. Dihydrorhodamine 123.
c. sucrose test.
d. cytometric bead array.

Answer 10

d. cytometric bead array.

Question 11

Many flow cytometry laboratories now use the CD45 marker in combination with SSC in differentiating various populations of WBCs to replace which of the following combinations?

a. CD4 + SSC
b. CD4 + FSC
c. FSC + SSC
d. FSC + CD45

Answer 11

c. FSC + SSC

Question 12

Which of the following statements best describes a single-parameter histogram?

a. Each event is represented by a dot.
b. Data are distributed in four quadrants.
c. Positive and negative events are plotted on the x- and y-axes.
d. A chosen parameter is plotted versus the number of events.

Answer 12

d. A chosen parameter is plotted versus the number of events.

Question 13

Which of the following statements regarding PNH is NOT correct?

a. PNH could affect RBC and WBC counts.
b. Patients with PNH usually present with symptoms such as hemolytic anemia.
c. Flow cytometry can diagnose PNH by detecting missing anchor proteins.
d. PNH is an immunodeficiency disease that is caused by environmental factors.

Answer 13

d. PNH is an immunodeficiency disease that is caused by environmental factors.

Question 14

Which type of analyzer allows one to measure multiple analytes from numerous samples, loaded at any time?

a. Batch analyzer
b. Random-access analyzer
c. Front-end-loaded analyzer
d. Sequential access analyzer

Answer 14

b. Random-access analyzer

Question 15

Operational considerations when selecting automated analyzers for a laboratory include which of the following?

a. Reagent stability
b. Test menu
c. Stat capability
d. All of the above

Answer 15

d. All of the above

Question 16

Analyzers use different methods for mixing, including magnetic stirring, rotation paddles, and forceful dispensing. Whichever method is used, it is imperative that

a. reagents should always be kept refrigerated.
b. there is no splashing or carryover between samples.
c. samples are kept at room temperature.
d. multiple methods are not used simultaneously.

Answer 16

b. there is no splashing or carryover between samples.

Question 17

All of the following are benefits of automation except

a. greater accuracy.
b. reduced turnaround time.
c. savings on reagents.
d. controls are no longer needed.

Answer 17

d. controls are no longer needed.

Question 18

If an analyzer gets different results each time the same sample is tested, what type of problem does this represent?

a. Sensitivity
b. Specificity
c. Accuracy
d. Precision

Answer 18

d. Precision